Brain Structure and Function

, Volume 222, Issue 4, pp 1645–1662

Revisiting the human uncinate fasciculus, its subcomponents and asymmetries with stem-based tractography and microdissection validation

  • Janice Hau
  • Silvio Sarubbo
  • Jean Christophe Houde
  • Francesco Corsini
  • Gabriel Girard
  • Charles Deledalle
  • Fabrice Crivello
  • Laure Zago
  • Emmanuel Mellet
  • Gaël Jobard
  • Marc Joliot
  • Bernard Mazoyer
  • Nathalie Tzourio-Mazoyer
  • Maxime Descoteaux
  • Laurent Petit
Original Article

DOI: 10.1007/s00429-016-1298-6

Cite this article as:
Hau, J., Sarubbo, S., Houde, J.C. et al. Brain Struct Funct (2017) 222: 1645. doi:10.1007/s00429-016-1298-6

Abstract

Despite its significant functional and clinical interest, the anatomy of the uncinate fasciculus (UF) has received little attention. It is known as a ‘hook-shaped’ fascicle connecting the frontal and anterior temporal lobes and is believed to consist of multiple subcomponents. However, the knowledge of its precise connectional anatomy in humans is lacking, and its subcomponent divisions are unclear. In the present study, we evaluate the anatomy of the UF and provide its detailed normative description in 30 healthy subjects with advanced particle-filtering tractography with anatomical priors and robustness to crossing fibers with constrained spherical deconvolution. We extracted the UF by defining its stem encompassing all streamlines that converge into a compact bundle, which consisted not only of the classic hook-shaped fibers, but also of straight horizontally oriented. We applied an automatic-clustering method to subdivide the UF bundle and revealed five subcomponents in each hemisphere with distinct connectivity profiles, including different asymmetries. A layer-by-layer microdissection of the ventral part of the external and extreme capsules using Klingler’s preparation also demonstrated five types of uncinate fibers that, according to their pattern, depth, and cortical terminations, were consistent with the diffusion-based UF subcomponents. The present results shed new light on the UF cortical terminations and its multicomponent internal organization with extended cortical connections within the frontal and temporal cortices. The different lateralization patterns we report within the UF subcomponents reconcile the conflicting asymmetry findings of the literature. Such results clarifying the UF structural anatomy lay the groundwork for more targeted investigations of its functional role, especially in semantic language processing.

Keywords

White matter anatomy Uncinate fasciculus Healthy human Brain asymmetry Diffusion-imaging tractography Klingler’s dissection 

Supplementary material

429_2016_1298_MOESM1_ESM.pptx (17.2 mb)
Anatomical plates of the principal streamlines of the five subcomponents of the uncinate fascicle superimposed on coronal views of the MNI single-subject from y =+55 mm to y = -40 mm. Plate 1: dorsal UF (in red); Plate 2: ventro-lateral UF (in green); Plate 3: ventro-medial UF (in yellow); Plate 4: short posterior ventro-medial UF (in cyan); Plate 5: short anterior ventro-medial UF (in orange). L: left; R: right (PPTX 17570 kb)
429_2016_1298_MOESM2_ESM.docx (149 kb)
Supplementary material 2 (DOCX 149 kb)

Funding information

Funder NameGrant NumberFunding Note
LabEx TRAIL Bordeaux
  • ANR-10-LABX-57
Agence Nationale de la Recherche
  • BIOMIST - no. ANR-13-CORD-0007

Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Janice Hau
    • 1
  • Silvio Sarubbo
    • 2
    • 3
  • Jean Christophe Houde
    • 4
  • Francesco Corsini
    • 2
    • 3
  • Gabriel Girard
    • 4
  • Charles Deledalle
    • 5
  • Fabrice Crivello
    • 1
  • Laure Zago
    • 1
  • Emmanuel Mellet
    • 1
  • Gaël Jobard
    • 1
  • Marc Joliot
    • 1
  • Bernard Mazoyer
    • 1
  • Nathalie Tzourio-Mazoyer
    • 1
  • Maxime Descoteaux
    • 4
  • Laurent Petit
    • 1
  1. 1.Groupe d’Imagerie Neurofonctionnelle, Institut des Maladies Neurodégénératives-UMR 5293, CNRS, CEAUniversity of Bordeaux, PAC CarreireBordeauxFrance
  2. 2.Division of Neurosurgery, Department of Neurosciences“S. Chiara” Hospital, Trento APSSTrentoItaly
  3. 3.Structural and Functional Connectivity Lab, Division of Neurosurgery“S. Chiara” Hospital, Trento APSSTrentoItaly
  4. 4.Sherbrooke Connectivity Imaging LabUniversity of SherbrookeSherbrookeCanada
  5. 5.Institut de Mathématiques de Bordeaux-UMR 5251, CNRSTalenceFrance

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